PROJECT SUMMARY Recent advances in stem cell biology hold great potential in developing new approaches for the treatment of many devastating diseases, including musculoskeletal disorders (MSDs). Stem cell-based therapies for regenerating functional muscle cells and restoring muscular functions to damaged skeletal muscles can be critical for the development of therapeutic advances in musculoskeletal disease and disorder. Such approaches, however, require the generation of engraftable cell sources of functional myogenic cells and better control of stem cell myogenic differentiation in an effective, selective, and safe manner. To this end, the main goal of this proposal is to develop a bio-inspired platform that can replicate the structure and function on endogenous proteins called transfection factors (TFs; MyoD and Myogenin), which are specific for muscle-specific genes and responsible for orchestrating overall stem differentiation into muscle cells. Our bio-inspired platform called NanoScript, is a nanoparticle-based transcription factor that behaves and function just like natural TF proteins. This NanoScript platform is designed to be gene-specific and can effectively activate targeted gene expressions (e.g. MyoD, Myogenin and the related endogenous genes) in a non-toxic and non- viral manner. Out central hypothesis, based upon recent achievement and preliminary data, is that our proposed NanoScript platform can effectively generate functional muscle cells from human patient-derived adipose- derived mesenchymal stem cells (AMDSCs), which are an abundant source of stem cells, with patient-specific stem cells treatment possibilities. We propose to test our central hypothesis and achieve our objectives by addressing the following specific aims: Aim1: Design and synthesize muscle cell-specific TFs (MRF) and epigenetic modulators for the construction of enhanced muscle cell-specific NanoScripts [NanoScripts-MRF]. Aim2: Utilize NanoScript to activate muscle-specific genes in ADMSCs for generating muscle cells. The proposed research is innovative, as this concept of developing a TF emulator by integrating two multidisciplinary approaches (chemical biology and nanomedicine) onto a single nano-platform for non-viral gene regulation in stem cells has not been developed. The proposed research is significant, since we will develop an innovative technology platform and our NanoScript is an easily tunable and robust platform, it can be further developed to combine with epigenetic modulators or other synergists for effective and selective induction of functional muscle cells. Collectively, upon successful completion of the proposed study, our expectations are that NanoScript-MRF will activate transcription of the muscular-specific genes containing their cognate TF consensus DNA binding domain, which will lead to an enhanced stem differentiation into muscle cells. Because NanoScript is non-toxic and non-viral, the generated muscle cells will be considered for translation into in vivo animal studies in future studies.